Civilizations
Cultures
The cultures mentioned aren't to do with the social aspect of the game, but they are various 'Barbarian' cultures that are grouped together in specific areas of the map. They only engage in raiding activities, but your stance with the particular culture reflects how much that they attempt to raid you civilization, so if your civilization oppresses the culture on a regular basis, then the amount of 'freedom fighting' significantly increases. They will also occasionally raid in force, this means that Task Forces belonging to a culture are generated and they will attack with them. Cultures are shown in pastel colours.
Civilizations
Civilizations represents the nations which cover a significant area of land ('Barbarian Cultures' are civilizations, but they only hold a small portion of land, so they are grouped together into a different category). Civilizations have a lot more power than cultures, both in the military and economic sense, and they possess the power to shape the future of the world on a large scale. Civilizations are shown in dark colours.